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Hit or miss: Glacial incisions of snowball Earth
Author(s) -
Mitchell Ross N.,
Ger Thomas M.,
Nordsvan Adam,
Cox Grant M.,
Li ZhengXiang,
Hoffman Paul F.
Publication year - 2019
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/ter.12400
Subject(s) - snowball earth , geology , glacial period , rodinia , supercontinent , paleontology , glacier , rift , craton , tectonics
Abstract Estimated at ~58 Ma in duration, the Sturtian snowball Earth (ca. 717–659 Ma) is one of the longest‐known glaciations in Earth history. Surprisingly few uncontroversial lines of evidence for glacial incisions associated with such a protracted event exist. We report here multiple lines of geological field evidence for deep but variable glacial erosion during the Sturtian glaciation. One incision, on the scale of several kilometres, represents the deepest incision documented for snowball Earth; another much more modest glacial valley, however, suggests an erosion rate similar to sluggish Quaternary glaciers. The heterogeneity in snowball glacial incisions reported here and elsewhere was likely influenced by actively extending horst‐and‐graben topography associated with the breakup of supercontinent Rodinia.